640326634432 has 56 divisors (see below), whose sum is σ = 1289453230080. Its totient is φ = 315431397120.

The previous prime is 640326634399. The next prime is 640326634433. The reversal of 640326634432 is 234436623046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640326634433) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6489853 + ... + 6587779.

Almost surely, 2^640326634432 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640326634432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (644726615040).

640326634432 is an abundant number, since it is smaller than the sum of its proper divisors (649126595648).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640326634432 is a wasteful number, since it uses less digits than its factorization.

640326634432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99449 (or 99439 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 43.

The spelling of 640326634432 in words is "six hundred forty billion, three hundred twenty-six million, six hundred thirty-four thousand, four hundred thirty-two".